1. Field of the Invention
The present invention relates to landing gear arrangements, and more particularly to a landing gear extension system that includes landing gear and doors covering the landing gear, and which uses a pyrotechnically initiated high pressure bottle to activate the extension system.
2. Description of the Related Art
Landing gear extension systems are well known in the art, as are pneumatic operating systems.
U.S. Pat. No. 2,758,807 to Ryan discloses an apparatus for effecting retraction of landing gear on an aircraft in which the apparatus uses an explosive cartridge to initiate operation of the apparatus. The system does not employ pressurized gas contained in a bottle.
U.S. Pat. No. 4,052,024 to Smith discloses a pneumatic gear motor for use with aerospace vehicle control fins is controlled by a servo valve which is fed by pressurized gas from a reservoir. An inert gas in the reservoir is heated to further increase the pressure in the reservoir by an explosive charge housed adjacent the reservoir. The heated inert gas is then released to a pressure control valve before being passed to the gear motor.
U.S. Pat. No. 5,184,465 to Howard et al. teaches a hydraulically driven actuator for raising and lowering aircraft landing gear. The patent fails to disclose sequential operation of the landing gear and its housing doors.
Other control systems for high performance air vehicles include those disclosed in U.S. Pat. No. 4,754,940 to Deter, U.S. Pat. No. 5,460,340 to White, and U.S. Pat. No. 4,793,137 to Musk.
While many of these previously proposed systems use pressurized gas from a reservoir and are useful for operation of aircraft landing gear, control fins and flaps, none disclose the use of pressurized gas to sequentially actuate the landing gear doors and then the landing gear itself. Further, the prior art devices include gas cannisters that are of significant size to achieve the desired action, and therefore require frequent replenishment to maintain the requisite pressure. Such service procedures are excessively labor-and cost-intensive.
Against this background of known technology, the applicant has developed a novel system for deploying aircraft landing gear and doors in the event of hydraulic or other failure. The system uses a high pressure gas bottle charged to very high pressure, on the order of 6500 psi or higher, which can be opened by a pyrotechnically fired disk cutter to allow the gas in the bottle to flow out. The gas is then regulated to safer pressures and passed to valving which sequentially controls hydraulically operated landing gear and associated housing doors.